JPH0996991A - Heat-fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of reducing power consumption, as well as reducing the temp. ripple irrespective of a kind of recording material or the like, even in the case of adopting the fixing device of film system. SOLUTION: When setting a section being not successively irradiated with the light beyond a specific length corresponding to the peripheral direction of a photosensitive drum as a non-printing area for instance, the printing pattern of the certain recording material turns out, as shown in figures, a blank (a), a printing area (b), the bland (c),..., then with respect to the blank (a), the temp. is controlled at the low temp. T1, during the time between ta and (t) considering the temp. rising time (t) of a heating body, and with respect to the printing area (b), the temp. is controlled at the high temp. T0, during tb second, thus the power consumption is saved by reducing the power supplying proportion to the heating body on the non-printing area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film heating type heat fixing device, and an image forming apparatus such as an electrophotographic printer, a copying machine and an electrostatic recording device provided with this heat fixing device.

[0002]

2. Description of the Related Art Conventionally, as a fixing method for fixing an unfixed image on a recording material, a contact heating type fixing device having good thermal efficiency and safety has been widely used. Among them, from the viewpoint of energy saving, there is a film heating type heat fixing apparatus which heats a film having a very small heat capacity from the inside, which has a high energy efficiency and a quick rise of the surface temperature, and is disclosed in JP-A-63-
No. 313182, JP-A-2-15778,
JP-A-4-44075-44083, JP-A-4-440
No. 204980-204984.

Specifically, a thin heat-resistant film (or sheet), a means for moving the film, and a fixed temperature control which is fixedly supported on one side of the film with the film in the middle. A heating member (heater) and a pressing member which is disposed on the other surface side of the heating member so as to face the heating member and makes the developer image-bearing surface of the recording material to be image-fixed adhered to the heating member via the film. And at least when performing image fixing, the film is run and moved at substantially the same speed in the forward direction of the recording material conveyed and introduced between the film and the pressure member, and the run moving film is sandwiched. By passing through the fixing nip portion formed by pressure contact between the heating member and the pressure member, the developer image carrying surface of the recording material is heated by the heating member through the film, and pressure is applied at the fixing nip portion. Allows the developer image to be softened and melted and permanently applied to the recording material. It is intended to fix the image.

FIG. 15 shows a schematic structure of a specific example thereof. FIG. 16 is a plan view of the heating body with a part of the heating element omitted and a block diagram of the energization control system.

In FIG. 15, reference numeral 1 denotes a heat-resistant film (fixing film) in the form of an endless belt, which comprises a driving roller 11 arranged substantially parallel to each other, a driven roller 12 also serving as a tension roller, and a heating element (heater) 2. Suspended between the three members.

The film 1 has a total thickness of 100 μm in order to reduce the heat capacity and improve the quick start property.
Below, preferably 40μm or less 20μm or more heat resistance ·
PTFE, PFA, PPS with releasability and strength durability
Or a single layer film such as polyimide, polyamide imide, PEEK, PES, etc.
It is a composite layer film or the like coated with PFA, FEP or the like as a release layer.

Numeral 13 is a heat holder for supporting the heating element 2 in adiabatic manner, 10 is a silicone rubber or the like for sandwiching the film 1 between the heating element 2 and the film 1 and pressing the film 1 against the surface of the heating element 2 at a total pressure of 4 to 15 kg. Is a pressure roller having a rubber elastic layer having good releasability.

By rotating the driving roller 11, the film 1 is brought into close contact with the surface of the heating body 2 in a clockwise direction indicated by an arrow at least during image fixing, and slides on the surface of the heating body 2 at a predetermined peripheral speed. That is, it is rotationally driven without wrinkles at substantially the same peripheral speed as the conveying speed of the recording material P carrying the unfixed toner image T conveyed from the image forming section (A) side.

The heating element 2 includes an energization heating element (resistance heating element) 4 as a heat source that generates heat by supplying electric power, as will be described later, and is heated by the heat generation of the energization heating element 4.

Therefore, in a state where the heating element 2 is heated by the power supply to the energization heating element 4 and the film 1 is rotationally driven, the pressure contact portion N (fixing nip portion) between the heating element 2 and the pressure roller 10 is formed. By introducing the recording material P between the film 1 and the pressure roller 10, the recording material P
When the recording material P is in close contact with the film 1 and passes through the fixing nip portion N while overlapping with the film 1, heat energy is applied to the recording material P from the heating body 2 through the film 1 in the course of passing the recording material P through the fixing nip portion. Then, the unfixed toner image T on the recording material P is heated and melted and fixed, and the recording material P is separated and discharged from the film 1 after passing through the fixing nip portion.

As shown in FIG. 16, this heating element 2 has the following characteristics: a) Electrical insulation of Al ₂ O ₃ (alumina), AlN, SiC, etc., whose longitudinal direction is substantially orthogonal to the moving direction of the film 1. An elongated ceramic substrate 3 having heat resistance and low heat capacity; and b) formed in a linear or strip-like shape along the substrate longitudinal direction at the central portion in the substrate width direction on one surface side (front surface side) of the substrate 3.
Silver palladium (Ag / Pd) as a heat source, Ru
An energization heating element 4 such as O ₂ or Ta ₂ N; c) feeding electrodes 5 and 6 formed on the surface of the substrate 3 by electrically conducting both ends of the energization heating element 4; d) energization heating of the substrate 3 An electrically insulating overcoat layer 7 made of glass or the like as a surface protective layer covering the body forming surface, and e) a temperature detecting element 8 such as a thermistor provided in contact with the other side surface (back surface side) of the substrate 3, And a temperature fuse 9 as a safety temperature detecting element (thermal protector).

As shown in FIG. 15, the heating element 2 has a film contact sliding surface side on the overcoat layer 7 side, and this heating surface 2 is exposed to the outside to form a heat-insulating heat holder 13. It is fixedly supported by a supporting portion (not shown) via the intermediary.

Further, as shown in FIG. 16, the heating element 2 has an AC power source 2 between the power supply electrodes 5 and 6 at both ends of the energization heating element 4.
A voltage is applied from 0, and the energization heating element 4 generates heat to raise the temperature. The temperature of the heating element 2 is detected by the temperature detection element 8 on the back surface of the substrate 3, and the detection information is fed back to the energization control circuit 15. As a result, the energization of the energization heating element 4 from the AC power source 20 is controlled, so that the temperature detection element 8 is activated during fixing.
The temperature of the heating element 2 detected at is a predetermined temperature (fixing temperature)
The temperature is controlled so that

The temperature of the heating element 2 is controlled by controlling the voltage or current applied to the energizing heating element 4 or the energizing time.
Methods for controlling the energization time include zero-cross wave number control for controlling energization and suspension of energization for each half-wave of the power supply waveform, and phase control for controlling a phase angle for energization for each half-wave of the power supply waveform.

That is, the output of the temperature detecting element 8 is A / D converted and taken into the CPU, and based on the information, pulse width modulation such as phase control or wave number control is applied to the AC voltage applied to the energization heating element 4 by the triac. Then, the energization heating element 4 is applied so that the temperature detected by the temperature detecting element 8 is constant.
It controls the energization to.

Further, the temperature detecting element 8 keeps the recording material passing portion of the heating element 2 at a constant temperature regardless of the size of the recording material as the material to be heated. It is arranged at a position corresponding to the passage area.

Further, the thermal fuse 9 is connected in series to the energization path for the energization heating element 4 and arranged in contact with the back surface of the substrate 3 of the heating element 2, so that energization control of the energization heating element 4 is impossible. When a situation occurs and the temperature of the heating element 2 rises abnormally (runaway of the heating element), the thermal fuse 9 is activated and the energization heating element 4 is activated.
The energizing circuit for the energizing element 4 is opened, and the energizing of the energizing heating element 4 is turned off.

The film heating type apparatus as described above,
Since the heating element 2 having a small heat capacity can be used, the weight time can be shortened (quick start) as compared with the conventional heat fixing device such as a heat roller system, and the quick start is possible. Preheating when not in use is unnecessary, and power saving can be achieved in a comprehensive sense.

[0019]

However, in the heat fixing device as in the above-mentioned conventional example, the heating body can be finely energized by wave number control, phase control or the like so that the heating body can maintain the optimum temperature for fixing. Even if the energization control is performed on, the fixing property is guaranteed assuming the case where the image information ratio is the maximum, regardless of the amount of image information on the recording material, resulting in high power consumption. There was a tendency.

Further, the conventional energization control for the heating body by phase control, wave number control, etc. is performed by the type of recording material (thick paper, thin paper, etc.), paper state (paper water supply amount, paper temperature, etc.). It was done without depending on the recording material, depending on the recording material film, heating element,
The amount of heat taken from the pressure roller or the like is different, and the temperature ripple of the heating body may change depending on the recording material.

In FIG. 17, the wave number is controlled with an AC voltage of f = 50 Hz and V _AC = 110 V with the fundamental wave number of the wave number control being 20 waves, and when the temperature of the heating element is adjusted to a constant temperature of 180 ° C., the temperature is thick. It shows the temperature ripple of the heating element when fixing paper and thin paper.

As shown in FIG. 17, in the case of thin paper, the maximum temperature ripple is about 3 ° C., whereas in the case of thick paper it reaches a maximum of about 9 ° C., causing fixing failure. There was an occasion.

Therefore, the present invention provides a fixing device and an image forming apparatus capable of reducing the power consumption and reducing the temperature ripple irrespective of the type of recording material even when a film type fixing device is used. It is intended to be provided.

[0024]

According to the first invention of the present application, the above object is to make a heat-resistant film contact and slide on a heating body and record on the surface of the film opposite to the heating body. A heat-fixing device that slides a material in close contact with the film and passes the film through a position of a heating body to apply heat energy from the heating body to the recording material through the film to fix an unfixed image on the recording material as a permanent image. In the heat fixing device having a temperature detecting means for the heating body and a means for controlling the energization of the heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature, Based on this, it is achieved by reducing the rate of energization of the heating element to the non-printed area.

According to the second invention of the present application,
The above-mentioned object is achieved in the above-mentioned first invention by controlling the heating body temperature so that the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area.

Further, according to the third invention of the present application, in the above-mentioned first invention, the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area. Thus, the heating element temperature in the non-printed area is achieved by varying it according to the length of the non-printed area.

Further, according to the fourth invention of the present application,
The above-mentioned purpose is to slide the heat-resistant film on the heating element in a contact manner,
A recording material is slid on the surface of the film opposite to the heating body, and the recording material is passed through the position of the heating body together with the film to give thermal energy to the recording material from the heating body through the film. A heat fixing device for fixing the unfixed image as a permanent image, and means for controlling the energization of the heating body so that the temperature detecting means of the heating body and the temperature detected by the temperature detecting means are maintained at a constant temperature. In the heat fixing device having, based on the image information of the recording material, when the non-printing area is at the heating member position, the energization of the heating member is stopped for an extremely short time, and based on the temperature change of the heating member at that time, This is achieved by determining the temperature control temperature according to the supplied recording material.

Further, according to the fifth invention of the present application, the above object is to bring a heat-resistant film into contact with and slide on a heating body, and slide a recording material onto the surface of the film opposite to the heating body. Moving the film through the heating element position with the film,
A heating and fixing device for applying heat energy from a heating body to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of the heating body and a temperature detected by the temperature detecting means. In a heat fixing device having a means for controlling the energization of the heating element so that the temperature is maintained at a constant temperature, when the non-printed area is at the position of the heating element based on the image information of the recording material, By stopping the energization for an extremely short time, measuring the temperature change of the heating element at that time, and determining the temperature control temperature in the non-printing area according to the result of comparing the temperature change amount and the predetermined temperature change amount. To be achieved.

According to the sixth aspect of the present invention,
The above-mentioned object is such that a heating element parallel to the main scanning direction of the recording material slides a heat resistant film on a heating element divided into a plurality of parts, and the recording material is provided on the surface of the film opposite to the heating element. In a heating and fixing device that allows the unfixed image on the recording material to be fixed as a permanent image by applying heat energy to the recording material from the heating body through the film by passing it through the film and passing through the position of the heating element together with the film. In a heat fixing device having a temperature detecting means for each heating body and a means for controlling energization to each heating body so that the temperature detected by the temperature detecting means is maintained at a constant temperature, Based on the image information of, by reducing the rate of energization to the heating element corresponding to the non-printed portion, than the rate of energization to the heating element corresponding to the printed portion of the area on the recording material at the heating element position. To be achieved.

Further, according to the seventh invention of the present application, in the above-mentioned sixth invention, the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion. This is achieved by controlling the heating body temperature.

According to the eighth aspect of the present invention,
In the sixth aspect of the invention, the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion.
This is achieved by changing the length according to the length of the non-printed portion.

Further, according to the ninth invention of the present application, the above object is to bring a heat-resistant film into contact with a heating body and slide the recording material on the surface of the film opposite to the heating body. Moving the film through the heating element position with the film,
A heating and fixing device for applying heat energy from a heating body to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of the heating body and a temperature detected by the temperature detecting means. In an image forming apparatus equipped with a heating and fixing device having means for controlling the energization of the heating element so that the temperature of the heating element is maintained at a constant temperature, the energization of the heating element to the non-printing area is performed based on the image information of the recording material. Achieved by reducing the proportion.

That is, according to the first invention of the present application, when the ratio of the non-printing area occupying the recording material exceeds the predetermined value based on the image information of the recording material, the non-printing area for such non-printing area is set. Since the rate of energization to the heating element is reduced, the power consumption is reduced without impairing the fixing property in the print area.

According to the second aspect of the present invention,
In the first aspect of the invention, since the heating body temperature is controlled so that the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area, the power consumption is reduced without impairing the fixing property in the printing area. Reduce.

Further, according to the third invention of the present application, in the above-mentioned first invention, the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area. Since the heating element temperature in the printing area changes according to the length of the non-printing area, the temperature is appropriately raised when the heating element temperature in the non-printing area is switched to the heating element temperature in the printing area. Fixability is not impaired and power consumption is reduced.

According to the fourth invention of the present application,
Based on the image information of the recording material, when the non-printing area is at the position of the heating element, the energization of the heating element is stopped for an extremely short time, and the temperature change of the heating element at that time is used to adjust the recording material to be supplied. Since the temperature control temperature is determined, the temperature ripple is suppressed within a predetermined range and the power consumption is reduced regardless of the amount of heat absorbed by the recording material.

Further, according to the fifth invention of the present application, based on the image information of the recording material, when the non-printed area is at the position of the heating body, the energization to the heating body is stopped for an extremely short time, and When the temperature change of the heating element is measured, the temperature control temperature in the non-printing area is determined according to the result of comparing the temperature change amount and the predetermined temperature change amount.
Further, regardless of the surrounding environment and the like, the temperature ripple is suppressed within a predetermined range, the fixing property in the print area is secured, and the power consumption is reduced.

According to the sixth aspect of the present invention,
When the heating element parallel to the main scanning direction of the recording material is divided into a plurality of parts, based on the image information of the recording material, the non-printed portion is more likely to be electrified than the heating element corresponding to the printed portion. Since the ratio of electricity to the corresponding heating element is reduced, the power consumption can be further reduced without impairing the fixing property.

Further, according to the seventh invention of the present application, in the sixth invention, the heating body temperature is set so that the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion. Is controlled, the power consumption is reduced without impairing the fixing property on the printed portion.

According to the eighth invention of the present application,
In the sixth aspect of the invention, the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion, and the heating body temperature in the non-printed portion depends on the length of the non-printed portion. Since the temperature is changed, the temperature is appropriately raised when the heating body temperature in the non-printed portion is switched to the heating body temperature in the printed portion, the fixing property in the printed portion is not impaired, and the power consumption is reduced.

Further, according to the ninth invention of the present application, in the image forming apparatus, when the ratio of the non-printing area in the recording material exceeds the predetermined value based on the image information of the recording material, the fixing device. Since the ratio of the energization of the heating element to the non-printing area in (3) is reduced, the power consumption is reduced without impairing the fixing property to the printing area.

[0042]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. FIG.
FIG. 1 is a diagram showing a schematic configuration of a laser beam printer which is an image forming apparatus according to a first embodiment of the present invention. The laser beam printer 30 of this embodiment is connected to a host computer, and after receiving the image information from the host computer, the controller expands it into bitmap data. The image information developed into the bit map data is sent to the engine unit of the laser beam printer 30 through the video interface, and the engine unit modulates the laser light by the scanner 31 based on the image information and performs a raster scan to obtain the desired information. Forming an image of. At this time, the controller and the engine part of the laser beam printer 30 are communicating as follows via the video interface.

First, the engine section transmits a ready signal when the recording material can be supplied and the printer can be operated by the signal from the controller. Next, the controller confirms that the ready signal from the engine unit is transmitted and transmits a print signal, which is a recording material supply command, to the engine unit. Upon receiving the print signal, the engine section immediately supplies the recording material P from the cassette 32 by the supply roller 33 and conveys it to the registration roller 34. The recording material P is temporarily stopped by the registration roller 34,
The engine unit can write an image after waiting for the rise of the scanner and the motor (not shown) provided in the scanner 34 and the completion of the preparatory rotation (so-called pre-rotation) for stabilizing the potential of the photosensitive drum 35. Wait until the state is reached.

After this, a vertical synchronization request signal notifying that the engine is ready to write an image is sent to the controller, and in response to this, the controller sends a vertical synchronization signal, and after a certain time, the image signal is sent. Send to the engine section. Then, after the engine section receives the vertical synchronizing signal, the recording material P is conveyed from the registration roller 34 to the transfer section.

Next, the photosensitive drum 35 having a photosensitive layer such as an organic photoconductor (OPC) is uniformly negatively charged by the charging roller 37, and then the engine portion is laser beam 38 modulated according to the above-mentioned image signal. Is irradiated onto the surface of the photosensitive drum 35. As a result, there is a difference in the amount of charge on the surface of the photosensitive drum between a portion irradiated with light and a portion not irradiated with light, and a desired electrostatic latent image is obtained.

Then, the electrostatic latent image is developed by the developing device 39 having negatively charged toner, visualized as a toner image T, electrostatically transferred to the recording material P by the transfer roller 36 at the transfer portion, and then recorded. The material P is conveyed to the fixing device 40, and the toner image is permanently fixed. The untransferred toner on the photosensitive drum 35 is cleaned by the cleaner 41, and the same image forming process is repeated again.

Next, the fixing device 40 in the above laser beam printer 30 will be described in detail. This fixing device 40, as shown in FIG. 1, has a total thickness of 100 μm or less, preferably 40 μm or less and 20 μm or more, which has heat resistance, releasability and strength durability.
Single layer film such as FA or PPS, or polyimide,
A driving roller 11 in which an endless belt-shaped fixing film 1 made of a composite layer film obtained by coating the surface of a film of polyamideimide, PEEK, PES or the like with PTFE, PFA, FEP or the like as a release layer, and substantially parallel to each other, The driven roller 12 which also functions as a tension roller,
A silicone rubber or the like which is stretched between the heating member 2 and the heating member 2 and the film 1 is sandwiched between the heating member 2 and the heating member 2 to press the film 1 against the surface of the heating member 2 at a total pressure of 4 to 15 kg. A pressure roller 10 having a rubber elastic layer with good releasability is provided.

Therefore, by the rotation of the driving roller 11, the fixing film 1 which is rotated in a clockwise direction indicated by an arrow in close contact with the surface of the heating body 2 while sliding on the surface of the heating body at a predetermined peripheral speed without wrinkles is provided. Then, the recording material P carrying the unfixed toner image T conveyed from the image forming section (A) side is introduced into the fixing nip portion N formed between the heating body 2 and the pressure roller 10. Then, heat energy is applied to the recording material P from the heating body 2 through the film 1 while the recording material P passes through the fixing nip portion, and the unfixed toner image T on the recording material P is heat-melted and fixed. .

The heating element 2 in this fixing device has a longitudinal direction that is substantially orthogonal to the moving direction of the fixing film 1.
Electrical insulation of l ₂ O ₃ (alumina), AlN, SiC, etc.
A heat-resistant and low-heat-capacity elongated ceramic substrate 3, and silver as a heat source formed in a linear or strip-like shape along the length of the substrate at the central portion in the substrate width direction on one surface side (front surface side) of this substrate 3. Energization heating element 4 made of palladium (Ag / Pd), RuO ₂ , Ta ₂ N, etc., feeding electrodes 5 and 6 formed on the substrate surface by conducting to both ends of this energization heating element 4, and energization of substrate 3 An electrically insulative overcoat layer 7 made of glass or the like as a surface protective layer covering the heating element forming surface and a temperature detection means such as a thermistor which is a temperature detection means provided in contact with the other side surface (back surface side) of the substrate 3. The element 8 and the temperature fuse 9 as a safety temperature detecting element (thermal protector) are provided, and the overcoat layer 7 side is exposed to the outside and a support portion (not shown) is provided via a heat insulating heat holder 13. ) To It is obtained by a constant support.

The temperature of the heating element 2 is detected by the temperature detecting element 8 on the back surface of the substrate, and the detected information is stored in the CPU 2
The temperature is controlled to a predetermined fixing temperature when fixing is performed by being fed back to the control unit 2 and controlling the energization of the energization heating element 4 from the AC power source (not shown) via the driver 23.

The temperature control is carried out in this manner in order to apply a predetermined heat energy to the recording material P via the film 1 so that the unfixed toner image T on the recording material P is satisfactorily heated and melted and fixed. .

Therefore, the unfixed toner image T is formed on the recording material P.
It is not necessary to apply the same heat energy to the area where the unfixed toner image T exists to the area where
In addition, if the same thermal energy is always applied, it leads to an increase in power consumption. Therefore, in the present embodiment, as shown in FIG. 1, the printing area and the non-printing area are distinguished based on the image information 21 from the host computer or the like, and the heating body 2 is controlled so that the heating temperature for each area is different. It was decided to control the energization of.

In the present embodiment, as shown in FIG. 3, a portion of the electrostatic latent image formed on the photosensitive drum 35 which is not continuously irradiated with light for 20 mm or more is set as a non-printing area, and other portions are printed. The area. If the non-printing area is between the front end of the recording material P and the beginning of the image information, the front end margin is set, and if the non-printed area is between the lines, the line and the picture, the picture and the picture, the line spacing is set. If it is between the end and the trailing edge of the paper, it is the trailing margin.

Then, the sizes of the non-printed area and the printed area are expressed as the time required for these areas to pass a predetermined position. In the fixing device, the switching timing of each area based on the time data, That is, the timing for switching the target temperature of the heating element is determined.

That is, as described above, the photosensitive drum 35
The irradiation of light onto the electrostatic latent image is started, and the electrostatic latent image is developed and transferred as a toner image onto the recording material P. Further, it takes t0 seconds before entering the nip portion of the fixing device 40. In summary, in the case of the image shown in FIG. 4,
The tip margin is the nip of the fixing device t0 seconds after the tip of the recording material P reaches a position (hereinafter, this position is referred to as a light irradiation position) when the irradiation of light on the photosensitive drum 35 is started. The first print area enters the nip portion after ta seconds. Thereafter, in the same manner, the last print area enters the nip portion because t0 + ta + tb + ... + te after the tip of the recording material P reaches the light irradiation position.
It will be in seconds.

Therefore, in the case of this example, when the tip of the recording material P reaches the light irradiation position, energization to the heating element 2 is started, the target temperature adjustment temperature is raised to T0, and t0 seconds elapse. From t0 to ta seconds before, the heater body 2 is energized at the target controlled temperature T1 in the non-printing area lower than T0, and t
After 0 + ta seconds has elapsed and before t0 + ta + tb has elapsed, the heater 2 is energized at the target temperature control temperature T0 in the print area, and the target temperature control temperature T1 in the non-print area is set to the target temperature control temperature T0 in the print area. By lowering the control (T1 <T0), the power consumption of the heating element can be reduced without impairing the conventional fixability. The target temperature of the heating element is determined from the result of detecting the temperature of the heating element with the temperature detecting element when the film heating and fixing device is started up.

The temperature control method according to this embodiment will be described in detail below with reference to FIG. 5 for an example of fixing an image as shown in FIG. In this embodiment, a copy sheet is used as the recording material P, and an apparatus capable of outputting eight A4 size sheets per minute is used.

First, as shown in FIG. 5, when the tip of the paper reaches the light irradiation position, energization to the heating element 2 is started,
The temperature of the heating element 2 at this time is detected, and the rate of temperature change Δt = dT / dt is measured. Next, from the measured Δt and the detected temperature of the heating element 2, the target temperature control temperature T0 in the print area is determined, and the target temperature control temperature T1 in the non-print area is based on this T0. Determined by T1 = T0-50 ° C. Then, the heating body 2 is energized by wave number control so that the temperature detected by the temperature detecting element 8 becomes these target controlled temperatures, and t0 seconds from the time when the front end of the paper reaches the light irradiation position. Up to T0
The heating element 2 is heated as.

Next, after t0 seconds, the front end of the paper is fixed to the fixing device 40.
At the time of entering the nip portion, the target temperature control temperature is switched to T1, and the low temperature temperature control is performed at T1 in the margin a. Since it takes ta seconds for the margin a to pass through the nip portion, it is preferable that the temperature is originally adjusted for T seconds at T1, but when the next printing area b is reached, the temperature is adjusted immediately for T0. Is difficult.
Therefore, the temperature control is performed at T1 only for a time obtained by subtracting the time t seconds estimated to rise the temperature of the heating element 20 from T1 to T0 from the above ta seconds, that is, ta '= ta-t seconds. . The time t is calculated from the above Δt.

As described above, after t0 seconds have passed from the point where the front end of the paper reaches the light irradiation position, the temperature control for the margin a is performed by setting the target temperature control temperature T1 for ta 'seconds, and t0 +
After ta 'seconds, the target controlled temperature is changed from T1 to T0 in preparation for the temperature control in the print area b. As a result, when the tip of the printing area b reaches the nip portion, the temperature of the heating element is adjusted to T0, and the heating element 2 is temperature-controlled at T0 for tb seconds in the printing area b.

Then, after t0 + ta + tb seconds, the margin c which is the non-printing area is formed again, so that the target controlled temperature of the heating element 2 is changed from T0 to T1 to control the temperature. Hereinafter, similarly, the target temperature control temperature is switched to T0 and T1, and the temperature control is performed.

Table 1 is a comparison of the power consumptions when the image fixing as shown in FIG. 4 is continuously performed for the position time by the conventional temperature control and the temperature control according to the present invention.

[0064]

[Table 1]

As shown in Table 1, if the temperature control according to the present invention is used, the power consumption can be reduced by about 35%.

As described above, in this embodiment, the CP
U21 discriminates the printing area from the non-printing area based on the image information, sets the target temperature-controlled temperature in the printing area to T0, sets the target temperature in the non-printing area to T1, and controls the temperature by T0> T1. It was possible to reduce the power consumption of the heating element without impairing the fixing property in the tone control.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. Note that the schematic configurations of the image forming apparatus and the fixing device, and how to grasp the printing area / non-printing area are the same as those in the first embodiment, and thus the description thereof is omitted.

In this embodiment, the power supply to the heating element is controlled according to the length of the non-printing area, so that the power consumption of the heating element can be reduced without impairing the conventional fixing property. is there.

That is, if the temperature of the heating element is lowered too much when the non-printing area is short, it becomes impossible to raise the temperature to the target fixing temperature in the printing area.

However, when the non-printing area is long, the temperature of the heating element can be greatly lowered because the heating element has sufficient time to rise to the target fixing temperature.

Therefore, in the present embodiment, the target controlled temperature is changed according to the length of the non-printing area.

Hereinafter, the temperature control of the present embodiment will be described in detail with reference to FIG. 6 in an example of fixing an image as shown in FIG. In this embodiment, a copy sheet is used as the recording material P, and an apparatus capable of outputting eight A4 size sheets per minute is used.

First, as shown in FIG. 6, energization to the heating element 2 is started from the time when the front end of the paper reaches the light irradiation position,
The temperature of the heating element 2 at this time is detected, and the rate of temperature change Δt = dT / dt is measured. Next, the target controlled temperature T0 in the print area is determined from the measured Δt and the detected temperature of the heating element 2.

Since the leading edge of the paper reaches the nip portion of the fixing device 40 after t0 seconds from the light irradiation position, the heating element 2 reaches the target controlled temperature T0 just before the leading edge of the paper is about to enter the nip portion. When the temperature is controlled as described above, and the margin a of the paper enters the nip portion and at the same time the length of the margin a is recognized to be 23 mm, T0-25 which is a low temperature controlled temperature corresponding to the length of the non-printing area of 23 mm. Control the temperature at ℃.

That is, in this embodiment, the low temperature control temperature in the non-printing area is determined by dividing the temperature that can be raised as shown in Table 2 according to the length of the non-printing area.

[0076]

[Table 2]

Further, it is necessary to change the temperature control temperature before changing to the print area b so that the temperature can be immediately adjusted at the fixing temperature T0 when the margin a is changed to the print area b. This change timing is determined based on the table shown in Table 3.

Table 3 shows the time required to raise the temperature from the low temperature control temperature to the fixing temperature T0.

[0079]

[Table 3]

That is, after t0 + ta-t seconds which is a timing obtained by subtracting the time t required for raising the temperature to T0 from the time t0 + ta seconds which is the time to change from the margin a to the printing area b, the low temperature control is changed to the fixing temperature T0. To change the control.

Then, in the printing area b, the temperature is adjusted at the fixing temperature T0, and when the margin c enters the nip portion and the length of the margin c is recognized to be 42 mm, the non-printing area is 4 in Table 2.
Select T0-38 ° C which is the low temperature controlled temperature at 2mm,
The control is changed so that the temperature can be adjusted at this temperature.

Table 4 compares the power consumption amounts of the conventional temperature control and the temperature control of the present invention.

[0083]

[Table 4]

This is the power consumption when the image fixing as shown in FIG. 4 is continuously output for one hour. as a result,
As shown in Table 4, the power consumption of the heating element could be reduced by about 45%.

As described above, in the present embodiment, the temperature of the heating element is adjusted to the low temperature in the non-printing area at a temperature corresponding to the length of the heating element, and the heating temperature is adjusted to the fixing temperature T0 in the printing area. Compared to the temperature control of (1), the power consumption of the heating element could be suppressed without impairing the fixability.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. 7 and 8. Note that the schematic configurations of the image forming apparatus and the fixing device, and how to grasp the printing area / non-printing area are the same as those in the first embodiment, and thus the description thereof is omitted.

In the present embodiment, the target controlled temperature in the printing area is determined by using the margin at the leading end of the recording material to determine the target controlled temperature according to the type and state of the recording material. , Temperature control is performed by wave number control.

In the above-described embodiment, when there is no recording material in the nip portion of the heating element, the rising time of the heating element 2 is used to calculate the temperature change ratio Δt = dT / dt during that period from the heating element 2 The target controlled temperature T0 has been determined.

However, in the present embodiment, the margin at the tip of the recording material is used, and at the same time when the tip margin enters the nip portion of the heating element, the heating element is forcibly energized to be off for a short period of time. Since the temperature change rate Δt ′ = dT / dt is measured, the temperature change rate Δt ′ according to the type and state of the recording material can be obtained.

Therefore, from this Δt ', the target controlled temperature T0' of the recording material is determined, and fixing is performed at the temperature T0 ', which makes it possible to perform optimum fixing regardless of the type and state of the recording material.

In addition, in the margin, which is the non-printing area, the temperature is controlled to be lower than the target fixing temperature T0 'to reduce the power consumption of the heating element.

The temperature control of the present embodiment will be described in detail below with reference to FIG. 7 for an example of fixing an image as shown in FIG. In this embodiment, a copy sheet is used as the recording material P, and an apparatus capable of outputting eight A4 size sheets per minute is used.

First, as shown in FIG. 7, when the tip of the paper reaches the light irradiation position, energization of the heating element 2 is started,
The temperature of the heating element 2 at this time is detected, and the rate of temperature change Δt = dT / dt is measured. Also, the heating element 2 has already been
When the sheet is standing by and is waiting for the sheet, when there is no sheet in the nip portion of the heating element 2, the heating element 2 is forcibly energized to be turned off for a short time, and the rate of temperature change Δt during that period is = DT / dt is obtained, and the target fixing temperature T0 of the heating element 2 is determined from Δt obtained by any of these methods. Then, before the paper enters the nip portion of the heating body 2, the heating body 2 is heated to the fixing target temperature T0 and enters the standby state.

Next, at t0 seconds after the tip of the paper reaches the light irradiation position, it is detected that the tip of the paper enters the nip portion,
The heating element 2 is turned off for 0.2 seconds from the moment the front end of the paper enters the nip portion, and the temperature change ratio Δ
By measuring t ′ = dT / dt, the target fixing temperature T0 ′ is determined according to Δt ′.

Table 5 shows the temperature change rate Δt 'and the target fixing temperature T0'.

[0096]

[Table 5]

The target fixing temperature T0 'is set as the fixing temperature in the printing area, and the temperature control temperature T1 in the non-printing area is T1 = T.
The temperature was 0'-50 ° C.

Therefore, the low temperature control at the tip margin a is T0 '.
The time t required to increase the temperature from T1 to T0 ′ by 50 ° C. at −50 ° C. is calculated from Δt ′.

Therefore, after the time ta '= t0 + ta-t seconds obtained by subtracting the time t required for raising the temperature by 50 ° C. from the timing t0 + ta seconds at which the leading edge margin a changes to the printing area b,
The temperature control is changed from the low temperature control to the target fixing temperature t0 ', and the temperature is adjusted to the target fixing temperature T0' in the print area b.

Further, at the timing t0 + ta + tb at which the margin c which is the non-printing area is changed, the temperature control at the target fixing temperature T0 'is changed to the low temperature control.

FIG. 8 shows a cardboard (125 g / m 2 in this embodiment.
m ² ) shows the result of comparing the temperature ripple in the case of fixing the image as shown in FIG. 4 with the conventional temperature control.

As shown in FIG. 8, the conventional temperature control has a maximum temperature ripple of about 10 ° C., whereas the temperature control of the present invention can suppress the temperature ripple to about 3 ° C.

As described above, the target fixing temperature T0 'is determined and controlled by the margin of the leading edge of the recording material, and the fixing temperature suitable for the type and state of the recording material is determined, thereby minimizing the temperature ripple. be able to.

Table 6 is a comparison of the power consumptions when the image fixing as shown in FIG. 4 is continuously performed for 1 hour by the conventional temperature control and the temperature control according to the present invention.

[0105]

[Table 6]

As shown in Table 6, if the temperature control according to the present invention is used, the power consumption can be reduced by about 25%. As described above, in the temperature control according to the present invention, not only the temperature ripple can be minimized but also the power consumption can be reduced.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIGS. In addition,
The schematic configurations of the image forming apparatus and the fixing device, and the way of capturing the print area and the non-print area are the same as those in the first embodiment, and thus the description thereof is omitted.

In this embodiment, the rate of temperature change of the heating element in the non-printing area is compared with the predetermined rate of temperature change, and the temperature control of the heating element in the non-printing area is determined from the result. Is.

The temperature control in the present embodiment will be described in detail with reference to FIG. 9 for an example of fixing an image as shown in FIG. In this embodiment, a copy sheet is used as the recording material P, and an apparatus capable of outputting eight A4 size sheets per minute is used.

First, as shown in FIG. 9, when the tip of the paper P reaches the light irradiation position, energization to the heating body 2 is started, and while the heating body 2 is heated from the cold state, , The rate of temperature change Δt1 = dT / dt is measured, and this Δt1
Further, the target fixing temperature T0 of the heating element is determined and the heating element is heated to T0.

Next, when the margin a at the front end of the paper enters the nip portion, the heating body 2 is turned off for a short time. The temperature change Δt2 = dT / dt of the heating element 2 in this short time is measured.

Then, Δt1 and Δt2 are compared, and Δt1
If Δt2, consider that the amount of heat taken by the paper is large,
The temperature control in the margin a is controlled so that the temperature of the heating body becomes the target fixing temperature T0 when the printing area b is switched to.

On the other hand, if Δt1> Δt2, it is considered that the amount of heat absorbed by the paper is small, and the temperature control in the margin a is 50 ° C. lower than T0, as in the above embodiment, T1 = T0-50 ° C.
Control to control the temperature at low temperature.

In this way, the temperature change ratio Δt of the heating element is measured in the margin and compared with Δt1 to determine the temperature control in the non-printing area.

FIG. 10 shows the temperature ripple of the heating element in the temperature control of this embodiment and the conventional example when the image shown in FIG. 4 is fixed on the recording material left in a high temperature and high humidity environment for a long time. Indicated.

In the conventional temperature control as shown in FIG. 10, the maximum temperature ripple is about 11 ° C., while the present invention can suppress it to about 4 ° C.

By using the temperature control according to this embodiment, the target fixing temperature T0 initially predicted and set,
It is possible to perform temperature control such that the target fixing temperature T0 can be maintained after adding the type and condition of the paper and the surrounding atmosphere.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to FIGS. 11 to 14. In this embodiment, as shown in FIG. 11, the heating element is divided into three heating elements, and each heating element is capable of independently controlling the temperature.

How to recognize the print area / non-print area is shown in FIG.
As described above, the main scanning direction is divided into three, and the same understanding as that of the first embodiment is made, and thus the description thereof is omitted.

The description of the fixing device using the temperature control system of the present invention is also the same except that the heating element is divided into three parts as shown in FIG.

In the present invention, not the way to think of the non-printing area and the printing area, but the partial image information such as the non-printing area and the printing area, and the energization to the heating element of the three-divided film heat fixing device are synchronized. It is something to do.

In this embodiment, the target temperature T of each heating element is
0 is determined from the result of detecting the temperature of each heating element by each temperature detecting element when the film heating and fixing device is started up, and the target temperature control temperature T1 of the non-printing portion is the target of the printing portion. By controlling the temperature to be lower than the temperature control temperature T0, even if there is a printed portion and a non-printed portion in the two areas, it is possible to reduce the power consumption of the heating element without impairing the conventional fixing property. is there.

The present invention will be described below with reference to an example of fixing an image as shown in FIG. In this embodiment, the recording material P
As the copy paper, a device capable of outputting 8 sheets of A4 size paper per minute was used.

First, as shown in FIG. 14, when the tip of the paper reaches the light irradiation position, energization to the heating element is started,
The rate of temperature change Δt1 = dT / dt is measured while the heating element is heated from the cold state, and the target fixing temperature T0 of the heating element is determined from this Δt1. On the other hand, the low temperature control temperature T1 was set to T1 = T0-40 ° C., and the heating element was controlled by wave number control. Further, from Δt, the heating element is from T1 to T0.
The time t required to raise the temperature by 40 ° C. was calculated.

Then, when the leading edge of the paper is about to enter the nip portion of the fixing device 40, the heating element sets the target temperature control temperature T0.
When the print portion a at the leading end of the paper enters the nip portion, the heating elements a and a corresponding to the print portion a are temperature-controlled so as to maintain the target temperature control temperature T0 at the print portion. ,on the other hand,
The heating element C that does not correspond to the printing portion is controlled so as to be temperature-controlled at the target temperature-adjusted temperature T1.

Next, when the printing section a is changed to the printing section b,
The heating body a continues to be temperature controlled at T0, and the heating body c
After allowing for the time t required to increase the temperature from 1 to T0, the temperature is controlled to increase to T0. On the other hand, since the heating element A corresponds to the non-printing portion, the temperature control is changed to the low temperature control temperature T1.

Table 7 compares the power consumptions when the image fixing as shown in FIG. 13 is continuously performed for 1 hour by the conventional temperature control and the temperature control according to the present invention.

[0128]

[Table 7]

As shown in Table 7, if the temperature control of the present invention is used, the power consumption can be reduced by about 42%.

In this way, in the printing section, the target controlled temperature is set to T0.
By setting T1 in the non-printed portion and controlling the temperature of only the heating body corresponding to the printed portion with T0> T1, the consumption of the heating body is not impaired in the conventional temperature control. It is possible to reduce the amount of electric power.

[0131]

As described above, according to the first invention of the present application, when the ratio of the non-printing area in the recording material exceeds the predetermined value based on the image information of the recording material, Since the ratio of energization of the heating element to the non-printing area is reduced, not only power saving can be achieved, but also the fixing property to the printing area can be secured, and the optimum fixing state can always be maintained.

According to the second invention of the present application,
In the first aspect of the invention, since the heating body temperature is controlled so that the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area, the power consumption is reduced without impairing the fixing property in the printing area. Can be reduced.

Further, according to the third invention of the present application, in the above-mentioned first invention, the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area. Since the heating element temperature in the print area changes according to the length of the non-printing area, it is possible to appropriately raise the temperature when switching from the heating element temperature in the non-printing area to the heating element temperature in the printing area. Power consumption can be reduced without impairing the fixability in the area.

According to the fourth invention of the present application,
Based on the image information of the recording material, when the non-printing area is at the position of the heating element, the energization of the heating element is stopped for an extremely short time, and the temperature change of the heating element at that time is used to adjust the recording material to be supplied. Since the temperature control temperature is determined, the temperature ripple can be suppressed within a predetermined range and the power consumption can be reduced regardless of the amount of heat absorbed by the recording material.

Further, according to the fifth invention of the present application, when the non-printed area is at the position of the heating body, the power supply to the heating body is stopped for an extremely short time based on the image information of the recording material, and When the temperature change of the heating element is measured, the temperature control temperature in the non-printing area is determined according to the result of comparing the temperature change amount and the predetermined temperature change amount.
In addition, the temperature ripple can be kept within a predetermined range regardless of the surrounding environment, and the power consumption can be reduced without impairing the fixing property in the print area.

According to the sixth invention of the present application,
When the heating element parallel to the main scanning direction of the recording material is divided into a plurality of parts, based on the image information of the recording material, the non-printed portion is more likely to be electrified than the heating element corresponding to the printed portion. Since the ratio of electricity to the corresponding heating element is reduced, the power consumption can be further reduced without impairing the fixing property.

Further, according to the seventh invention of the present application, in the sixth invention, the heating body temperature is set so that the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion. Is controlled, the power consumption can be reduced without impairing the fixing property on the printed portion.

Further, according to the eighth invention of the present application,
In the sixth aspect of the invention, the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion, and the heating body temperature in the non-printed portion depends on the length of the non-printed portion. Since the temperature is changed, it is possible to appropriately raise the temperature when the heating body temperature in the non-printing portion is switched to the heating body temperature in the printing portion, and it is possible to reduce power consumption without impairing the fixing property in the printing portion.

Further, according to the ninth invention of the present application, in the image forming apparatus, when the ratio of the non-printing area in the recording material exceeds the predetermined value based on the image information of the recording material, the fixing device is used. Since the ratio of the energization of the heating element to the non-printing area is reduced, the power consumption can be reduced without impairing the fixing property to the printing area.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a heat fixing device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating how to grasp a print area and a non-print area in the first to fourth embodiments of the present invention.

FIG. 4 is an image sample used in the first to fourth embodiments of the present invention.

FIG. 5 is a relationship diagram between a non-printing area and a heating body temperature in the first embodiment of the present invention.

FIG. 6 is a relationship diagram between a non-printing area and a heating body temperature in the second embodiment of the present invention.

FIG. 7 is a relationship diagram between a non-printing area and a heating body temperature in the third embodiment of the present invention.

FIG. 8 is a diagram comparing the temperature ripples of the thick paper of the present invention and the conventional example.

FIG. 9 is a relationship diagram between a non-printing area and a heating body temperature in the fourth embodiment of the present invention.

FIG. 10 is a diagram comparing temperature ripples of a recording material left in a high temperature and high humidity environment for a long time in the present invention and a conventional example.

FIG. 11 is a schematic view of a heating body divided into three used in the fifth embodiment of the present invention.

FIG. 12 is a way of capturing a printed portion and a non-printed portion in a fifth embodiment of the present invention.

FIG. 13 is an image sample used in the fifth embodiment of the present invention.

FIG. 14 is a relationship diagram between a non-printing area and a heating body temperature in the fifth embodiment of the present invention.

FIG. 15 is a schematic view of a conventional film-type heat fixing device.

FIG. 16 is a schematic view of a heating body of a conventional film-type heat fixing device.

FIG. 17 is a temperature ripple when thick paper and thin paper are fixed by conventional temperature control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing film (heat resistant film) 2 Heating body 8 Temperature detecting element (temperature detecting means) 10 Pressure roller (pressurizing member) 21 CPU (means for controlling energization to heating body) P Recording material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoru Izawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yozozo Hotta 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (9)

[Claims] 1. A heat resistant film is brought into contact sliding contact with a heating body, a recording material is closely slid on the surface of the film opposite to the heating body, and the recording material is passed through the heating body position together with the film.
A heating and fixing device for applying heat energy from a heating body to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of the heating body and a temperature detected by the temperature detecting means. In a heat fixing device having a means for controlling the energization of the heating element so that the temperature of the heating element is maintained at a constant temperature, the ratio of the energization of the heating element to the non-printing area is reduced based on the image information of the recording material. And a heating and fixing device. 2. The heat fixing device according to claim 1, wherein the heating body temperature is controlled so that the heating body temperature in the non-printing area is lower than the heating body temperature in the printing area. 3. The heating element temperature in the non-printing area is lower than the heating element temperature in the printing area, and the heating element temperature in the non-printing area is changed according to the length of the non-printing area. The heat fixing device according to claim 1. 4. A heat-resistant film is brought into contact sliding contact with the heating element, a recording material is closely slid on the surface of the film opposite to the heating element, and the recording material is passed through the heating element position together with the film.
A heating and fixing device for applying heat energy from a heating body to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of the heating body and a temperature detected by the temperature detecting means. In a heat fixing device having means for controlling the energization of the heating element so that the temperature is maintained at a constant temperature, the energization of the heating element is performed when the non-printing area is at the heating element position based on the image information of the recording material. For a very short time,
A heat fixing device characterized in that a temperature control temperature according to a supplied recording material is determined based on a temperature change of a heating body at that time. 5. A heat resistant film is brought into contact sliding contact with the heating body, a recording material is closely slid on the surface of the film opposite to the heating body, and the recording material is passed through the heating body position together with the film.
A heating and fixing device for applying heat energy from a heating body to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of the heating body and a temperature detected by the temperature detecting means. In a heat fixing device having a means for controlling the energization of the heating element so that the temperature is maintained at a constant temperature, when the non-printed area is at the position of the heating element based on the image information of the recording material, Stop the energization for an extremely short time, measure the temperature change of the heating body at that time, and determine the temperature control temperature in the non-printing area according to the result of comparing the temperature change amount and the predetermined temperature change amount. Characteristic heating and fixing device. 6. A heating element parallel to the main scanning direction of the recording material,
A heat-resistant film is brought into contact sliding contact with a heating body divided into a plurality of parts, a recording material is closely slid on the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film. A heat fixing device for applying heat energy from a heating element to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of each heating element and the temperature detecting means of the heating element. In a heat fixing device having means for controlling energization to each heating body so that the detected temperature is maintained at a constant temperature, based on the image information of the recording material, an area on the recording material at the position of the heating body is detected based on the image information of the recording material. A heating and fixing device, characterized in that the ratio of energization to the heating body corresponding to the non-printed portion is reduced compared to the ratio of energization to the heating body corresponding to the printed portion. 7. The heating and fixing device according to claim 6, wherein the heating body temperature is controlled so that the heating body temperature in the non-printed portion is lower than the heating body temperature in the printed portion. 8. The heating body temperature in the non-printed portion is set lower than the heating body temperature in the printed portion, and the heating body temperature in the non-printed portion is changed according to the length of the non-printed portion. The heat fixing device according to claim 6. 9. A heat resistant film is brought into contact sliding contact with a heating body, a recording material is closely slid on the surface of the film opposite to the heating body, and the film is passed through the heating body position together with the film.
A heating and fixing device for applying heat energy from a heating body to a recording material via the film to fix an unfixed image on the recording material as a permanent image, the temperature detecting means of the heating body and a temperature detected by the temperature detecting means. In an image forming apparatus equipped with a heating and fixing device having means for controlling the energization of the heating element so that the temperature of the heating element is maintained at a constant temperature, the energization of the heating element to the non-printing area is performed based on the image information of the recording material. An image forming apparatus characterized by reducing the ratio.